It can be very difficult to keep a handicapped dog healthy without proper exercise. Without a dog wheelchair, many owners simply give up and have their pet euthanized years before it should be necessary.
A major obstacle for dog owners is the expense of buying a dog wheelchair. If you are in that position, consider building (or finding a sympathetic individual to help you build) a homemade dog wheel chair. Even a large one can be constructed much cheaper than commercial kinds, especially if you can scrounge rather than buy the materials.
For small dogs, a PVC frame can be built very easily. A strong, water resistant fabric can act as the support. PVC is very inexpensive and the amount of fabric you need does not cost much either. Your biggest expense will be the wheels. One recommendation is threaded, plastic caster wheels
For larger dogs, most frame designs have you construct a wheelchair using either wood or metal (usually aluminum). There is one design we ran across, however, that modifies a used human wheelchair, available relatively inexpensively at some thrift or medical supply stores.
To make either a wooden or metal homemade dog wheel chair, you will need a measuring tape, saw and power drill at a minimum. In addition, some metal designs call for soldering equipment. It is best to drill holes and use nuts and bolts to fasten pieces together. Add extra holes to allow for adjustments.
The supporting material for large dogs having problems with either their front or back legs usually consists of heavily padded webbing straps or brake wire suspended from the frame. Straps are often adjustable with buckles and sliders.
For a dog that needs support for all four legs, a sling made of canvas or other strong material is attached to the frame. It may be best to use safety pins to fasten this material prior to making the final adjustments and sewing them together. In all cases, the design should be such that the dog can go to the bathroom without dirtying the materials.
Wheels off an old bicycle, jogging stroller or human wheelchair are often used for larger dog wheelchairs. If the dog will be turning sharp corners, the axles can be set at an angle so the wheels lean inward a little to make it more stable. Wide, knobby tires will handle rougher terrain better than skinny ones. Thinner, lighter tires require less effort when your handicapped dog runs on asphalt or concrete.
Once you have finished building your homemade dog wheel chair it will be time to fine tune the adjustments. Watch your dog during movement for signs of misalignment and discomfort. Check for chafing from the supports.
Be patient while your dog gets used to this new contraption that follows him around!